Sounds like you could have a ground loop. I'd pick up some balanced, shielded, gold tipped TRS cables to avoid interference. Make sure you don't have any cables carrying a signal touching any power cables.

Your amp could have some issues, but I don't know enough about amps to give you any idea of what could be wrong.

If that doesn't help it could be an issue with your guitars pickup or wiring.

If all else fails try using a notch filter to eq it out of the recording.

It almost doesn't sound like a problem with the amp to me...I would start with the guitar, but also check the microphone. If you're recording it and hearing this, make sure it's not something with the recording device.

Most amps have a range of tonality that can be explored, but much more important is the overall voicing of the amp....the way it is wired on the board itself. That determines the overall personality of the amp, and the tone controls are just tweakage...

I'd have to say the same thing Ilwhyan said. A powerball isn't exactly cheap. One should only purchase something like that after playing it for awhile and liking the sound. If you really don't like the sound, then cut your losses and exchange it for something else. You've got more important things to worry about without being totally upset with your tone.

The Engl Powerball is an incredible amp for all genres of extreme metal. Many death metal bands have used it. For that matter, most of the amps Engl makes are great for metal. That being said, they do have a bit of a reputation for having a bit of ground hum. I've read about it plenty of times. I have an Engl E530 and it's kinda noisy also. Still sounds incredible, but you can notice the hum sometimes.

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